Field of the Invention
The present invention relates to a semiconductor device such as an IPM (Intelligent Power Module), and more particularly to a semiconductor device having a history function of an occurrence of an abnormal phenomenon.
Description of the Background Art
A conventional semiconductor device such as an IPM generally has a shutoff protection function for shutting off (turning off) a semiconductor element to be protected and outputting an error signal to the outside in order to protect a power chip on which a semiconductor element such as IGBT (Insulated Gate Bipolar Transistor) is mounted upon an occurrence of abnormality (error) such as high temperature generation and overcurrent. Examples of such semiconductor device having the shutoff protection function include an IPM disclosed in Japanese Patent Application Laid-Open No. 2003-88093.
The conventional IPM having the shutoff protection function shuts off a semiconductor element to be protected and outputs an error signal to the outside, but does not leave a history as to whether an abnormal phenomenon that causes the shutoff of the IPM occurs or not. Therefore, it is extremely difficult to find out the cause after the IPM is shut off due to an occurrence of trouble such as various abnormal phenomena. Specifically, the conventional IPM having the shutoff protection function entails a problem that an appropriate measure for an error after the shutoff cannot be taken, since the IPM cannot recognize why the semiconductor element is shut off.
The shutoff protection function of the conventional semiconductor device generally performs a shutoff protection operation uniformly at the time when the abnormal phenomenon exceeds a certain prescribed level. Specifically, the conventional semiconductor device shuts off the semiconductor element to be protected without determining whether the abnormal phenomenon causing the shutoff has a noteworthy level or a fatal error level. Therefore, the conventional semiconductor device has a problem of being non-user-friendly.